System and method for association of a guiding aid with a patient tissue

ABSTRACT

A guide for placing a landmark(s) in a patient tissue comprises a central portion defining at least one guiding bore configured to receive and guide a tool for placing the at least one landmark in the patient tissue. Extended portions project away from the central portion, each of the extended portions having respective lower base surfaces contoured to mate with the patient tissue, at least the respective lower base surfaces being customized as a function of preoperative imaging of the patient tissue, whereby the guide is specific to the patient.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Non-Provisional applicationSer. No. 15/787,931, filed on Oct. 19, 2017, which is a continuation ofU.S. Non-Provisional application Ser. No. 15/429,805, filed on Feb. 10,2017, which is a divisional of U.S. Non-Provisional application Ser. No.13/282,509, filed on Oct. 27, 2011 which claims priority to and thebenefit of U.S. Provisional Application No. 61/408,359, filed Oct. 29,2010, all of which are incorporated herein by reference in theirentireties.

TECHNICAL FIELD

The present invention relates to a system and method for association ofa guiding aid with a patient tissue and, more particularly, to a systemand method for associating at least one landmark with the patient tissuefor assisting with attachment of a stock prosthetic implant to thepatient tissue.

BACKGROUND OF THE INVENTION

In the installation of a prosthetic shoulder joint into a patient'sbody, a glenoid component is implanted into the glenoid vault of thepatient's scapula. An obverse surface of the glenoid component isconfigured for articulating contact with a humeral component carried bythe patient's humerus. A reverse surface of the glenoid component issecured to the bone surface of the glenoid vault.

Because the shoulder prosthesis is normally provided to correct acongenital or acquired defect of the native shoulder joint, the glenoidvault often exhibits a pathologic, nonstandard anatomic configuration. Asurgeon must compensate for such pathologic glenoid vault anatomy whenimplanting the glenoid component in striving to achieve a solidanchoring of the glenoid component into the glenoid vault. Detailedpreoperative planning, using two- or three-dimensional internal imagesof the shoulder joint, often assists the surgeon in compensating for thepatient's anatomical limitations. During the surgery, an elongated pinmay be inserted into the surface of the patient's bone, at apredetermined trajectory and location, to act as a passive landmark oractive guiding structure in carrying out the preoperatively plannedimplantation. This “guide pin” may remain as a portion of the implantedprosthetic joint or may be removed before the surgery is concluded. Thistype of pin-guided installation is common in any joint replacementprocedure—indeed, in any type of surgical procedure in which asurgeon-placed fixed landmark is desirable.

In addition, and again in any type of surgical procedure, modernminimally invasive surgical techniques may dictate that only a smallportion of the bone or other tissue surface being operated upon isvisible to the surgeon. Depending upon the patient's particular anatomy,the surgeon may not be able to precisely determine the location of theexposed area relative to the remaining, obscured portions of the bonethrough mere visual observation. Again, a guide pin may be temporarilyor permanently placed into the exposed bone surface to help orient thesurgeon and thereby enhance the accuracy and efficiency of the surgicalprocedure.

A carefully placed guide pin or other landmark, regardless of the reasonprovided, will reduce the need for intraoperative imaging in mostsurgical procedures and should result in decreased operative time andincreased positional accuracy, all of which are desirable in strivingtoward a positive patient outcome.

SUMMARY OF THE INVENTION

In an embodiment of the present invention, an apparatus for associatinga plurality of landmarks with a patient tissue is described. The patienttissue includes a primary patient tissue area and an anatomicallydifferentiated bordering secondary patient tissue area. The apparatus isat least partially customized responsive to preoperative imaging of thepatient tissue. Means are provided for mating with the primary patienttissue area in a preselected relative orientation. Means are providedfor fixing a first landmark to the primary patient tissue area in atleast one of a predetermined marking location and a predeterminedmarking trajectory. Means are provided for fixing a second landmark tothe secondary patient tissue area in at least one of a predeterminedmarking location and a predetermined marking trajectory.

In an embodiment of the present invention, an apparatus for associatinga plurality of landmarks with a patient tissue is described. Eachlandmark is associated with the patient tissue in at least one of apredetermined marking location and a predetermined marking trajectory.The patient tissue includes a primary patient tissue area and ananatomically differentiated bordering secondary patient tissue area. Theapparatus is at least partially customized responsive to preoperativeimaging of the patient tissue. A base has a lower base surface contouredto mate with both the primary and secondary patient tissue areas in apreselected relative orientation. The lower base surface is spaced apartfrom an upper base surface by a base body. A plurality of base aperturesextend between the upper and lower base surfaces through the base body.A plurality of guiding bosses protrude from the base. Each guiding bosshas a guiding bore extending therethrough. Each guiding bore extendscollinearly with a corresponding base aperture to permit insertion of alandmark through the apparatus. Each guiding bore and corresponding baseaperture cooperatively define at least one of the predetermined markinglocation and the predetermined marking trajectory for the landmark. Atleast one landmark is guided by the apparatus into engagement with amarking location in the primary patient tissue area and at least onelandmark is guided by the apparatus into engagement with a markinglocation in the secondary patient tissue area.

In an embodiment of the present invention, an apparatus for associatinga plurality of landmarks with a patient tissue is described. Eachlandmark is associated with the patient tissue in at least one of apredetermined marking location and a predetermined marking trajectory.The patient tissue includes a primary patient tissue area and ananatomically differentiated bordering secondary patient tissue area. Theapparatus is at least partially customized responsive to preoperativeimaging of the patient tissue. A base has a lower base surface contouredto mate with the primary patient tissue area in a preselected relativeorientation. The lower base surface is spaced apart from an upper basesurface by a base body. A stem has longitudinally separated first andsecond stem ends. The first stem end is attached directly to the baseand the stem extends upward from the base. At least one spacing arm isattached directly to the second stem end. Each spacing arm islongitudinally spaced from the base and has an arm guide aperturelaterally spaced from the stem. The arm guide aperture is configured toguide placement of a landmark inserted at least partially therethroughin at least one of the predetermined marking location and thepredetermined marking trajectory. The marking location is in thesecondary patient tissue area.

In an embodiment of the present invention, a method of associating aplurality of landmarks with a patient tissue is described. Each landmarkis associated with the patient tissue in at least one of a predeterminedmarking location and a predetermined marking trajectory. The patienttissue includes a primary patient tissue area and an anatomicallydifferentiated bordering secondary patient tissue area. A landmark guidehaving a base at least partially customized responsive to preoperativeimaging of the patient tissue is provided. The base has a lower basesurface contoured to mate with the primary patient tissue area in apreselected relative orientation. The base of the landmark guide ismated with the primary patient tissue area in a preselected relativeorientation. A first landmark is fixed to the primary patient tissuearea in at least one of the predetermined marking location and thepredetermined marking trajectory. A second landmark is fixed to thesecondary patient tissue area in at least one of the predeterminedmarking location and the predetermined marking trajectory.

In an embodiment of the present invention, an apparatus for associatinga plurality of landmarks with a patient tissue is described. Eachlandmark is associated with the patient tissue in at least one of apredetermined marking location and a predetermined marking trajectory.The removal of a predetermined amount of resection patient tissue andrearrangement of a remaining patient tissue is guided. The apparatus isat least partially customized responsive to preoperative imaging of thepatient tissue. A first guide is configured to contact the resectionpatient tissue and the remaining patient tissue and to guide surgicalcontact with the patient tissue. A first guide base has a lower firstguide base surface contoured to mate with both the resection andremaining patient tissues in a preselected relative orientation. Thelower first guide base surface is spaced apart from an upper first guidebase surface by a first guide base body. At least one first guidelandmark guiding aperture extends between the upper and lower firstguide base surfaces through the first guide base body to permitinsertion of at least one landmark therethrough. A plurality of firstguide cutting guide apertures extend between the upper and lower firstguide base surfaces through the first guide base body to permitpenetration of at least one cutting tool through the first guide. Atleast one of the first guide landmark guiding apertures defines at leastone of the predetermined marking location and the predetermined markingtrajectory for a first landmark and a plurality of the first guidecutting guide apertures each defines at least one cutting plane locationand orientation for a cutting tool to make at least one resection cutinto the patient tissue. The first guide is configured to cut theresection patient tissue for removal from the remaining patient tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be made tothe accompanying drawings, in which:

FIG. 1 is a side view of a first example use environment;

FIG. 2 is a front view of the example use environment of FIG. 1 ;

FIG. 3 is a partial perspective view of the example use environment ofFIG. 1 ;

FIG. 4 is a top view of an embodiment of the present invention;

FIG. 5 is a perspective bottom view of the embodiment of FIG. 4 from afirst side;

FIG. 6 is a perspective bottom view of the embodiment of FIG. 4 from asecond side;

FIG. 7 is a perspective top view of the embodiment of FIG. 4 from thesecond side;

FIGS. 8-10 are example user views of a program for generating theembodiment of FIG. 4 ;

FIG. 11 is a front view of the embodiment of FIG. 4 in a secondconfiguration;

FIG. 12 is a front view of the embodiment of FIG. 11 in a secondconfiguration in the example use environment of FIG. 2 ;

FIG. 13 is a top view of the embodiment of FIG. 4 in a thirdconfiguration;

FIG. 14 is a top view of the embodiment of FIG. 4 in a fourthconfiguration;

FIG. 15 is a top view of the embodiment of FIG. 4 in a fifthconfiguration;

FIG. 16 is a top view of a second example use environment;

FIG. 17 is a top view of an embodiment of the present invention;

FIG. 18 is a top view of the use environment of FIG. 16 as modifiedthrough the use of the embodiment of FIG. 17 ;

FIG. 19 is a side view of the embodiment of FIG. 17 in a secondconfiguration;

FIG. 20 is a partial bottom view of the embodiment of FIG. 19 ;

FIG. 21 is a schematic side view of the embodiment of FIG. 19 in the useenvironment of FIG. 16 ;

FIG. 22 is a perspective top view of the embodiment of FIG. 17 in athird configuration;

FIG. 23 is a perspective bottom view of the embodiment of FIG. 22 ;

FIG. 24 is a perspective side view of the embodiment of FIG. 22 ;

FIG. 25 is a front view of an embodiment of the present invention in athird example use environment;

FIG. 26 is a schematic side view of the embodiment of FIG. 25 ;

FIG. 27 is a front view of the embodiment of FIG. 25 in a secondconfiguration;

FIGS. 28A-28B depict an example use sequence of the second configurationof FIG. 27 ;

FIG. 29 is a schematic side view of the embodiment of FIG. 25 in a thirdconfiguration and in a fourth example use environment

FIG. 30 is a perspective top view of the embodiment of FIG. 17 in afourth configuration;

FIG. 31 is a perspective bottom view of the embodiment of FIG. 30 ;

FIG. 32 is a perspective top view of the embodiment of FIG. 17 in afifth configuration;

FIG. 33 is a perspective bottom view of the embodiment of FIG. 32 ;

FIG. 34 is a perspective top view of the embodiment of FIG. 17 in asixth configuration;

FIG. 35 is a perspective bottom view of the embodiment of FIG. 34 ;

FIG. 36 is a perspective top view of the embodiment of FIG. 17 in aseventh configuration;

FIG. 37 is a perspective bottom view of the embodiment of FIG. 36 ;

FIG. 38 is a perspective top view of the embodiment of FIG. 17 in aeighth configuration; and

FIG. 39 is a perspective bottom view of the embodiment of FIG. 38 .

DESCRIPTION OF EMBODIMENTS

The patient tissue is shown and described herein at least as a scapulaor a pelvis and the prosthetic implant component is shown and describedherein at least as a glenoid prosthetic shoulder component or anacetabular prosthetic hip component, but the patient tissue andcorresponding prosthetic implant component could be any desired typessuch as, but not limited to, hip joints, shoulder joints, knee joints,ankle joints, phalangeal joints, metatarsal joints, spinal structures,long bones (e.g., fracture sites), or any other suitable patient tissueuse environment for the present invention.

FIG. 1 depicts a portion of the external surface of a (left) scapula100, viewed from the anterior direction toward the posterior direction,which is an example of a possible patient tissue use environment for thedescribed systems, apparatuses, and methods. The humerus (not shown) ofa patient attaches to the scapula 100 at the glenoid fossa 102 to formthe ball-and-socket shoulder joint.

The glenoid fossa 102 is shown in greater detail in FIG. 2 , a viewtaken orthogonally from FIG. 1 . The term “lateral” is used herein torefer to a direction which, in FIG. 2 , lies substantially within theplane of the drawing as shown by directional arrow 104 and includes allof the superior, inferior, anterior, and posterior directions. The term“longitudinal” is used herein to refer to a direction definedperpendicular to the plane created by directional arrow 104, with thelongitudinal direction being substantially into and out of the plane ofthe drawing in FIG. 2 and representing the proximal (toward the medialplane of the body) and distal (out from the body) directions,respectively.

FIG. 3 is a partial perspective view of the scapula 100, with particularemphasis on the glenoid fossa 102. For the sake of discussion, theglenoid fossa 102 itself is referred to herein as a primary patienttissue area 108. That is, the primary patient tissue area 108 is aportion which directly receives an implant and/or is otherwise directlyaffected by a surgical procedure. In contrast, a secondary patienttissue area 110 is one which does not receive an implant and/or is notdirectly affected by a surgical procedure. In FIG. 3 , the secondarypatient tissue area 110 borders the primary patient tissue area 108 andis anatomically differentiated from the primary patient tissue area(i.e., the glenoid fossa 102) by the glenoid rim, indicatedapproximately by differentiation line 312. Here, the differentiationline 312 generally indicates an arbitrary (i.e., “depending onindividual discretion”) position along the continuous transition betweenthe glenoid fossa 102 and the supporting structures (e.g., the glenoidrim, the glenoid neck, the base of the coracoid, and/or the glenoidwall). However, regardless of the precise position of thedifferentiation line 312 for a particular application of the presentinvention, one of ordinary skill in the art should be able todistinguish between a primary patient tissue area 108 (one which isdirectly affected by a surgical procedure) and a secondary patienttissue area 110 (one which is incidentally affected by a surgicalprocedure, if at all) for the purposes of the present invention.

A distinction is made herein between the primary and secondary patienttissue areas 108 and 110 because the present invention relates to theassociation of at least one landmark with at least one of the primaryand secondary patient tissue areas. The term “landmark” is used hereinto indicate any guiding aid which serves as a detectable indicator of aparticular position on a “marked” substrate (here, the patient tissue).The landmarks discussed with respect to the present invention arepresumed to be affixed or otherwise rigidly associated with a particularpatient tissue so that a user can confidently maintain a sense ofphysical and/or visual orientation within the operative field. Suitablelandmarks may include, but are not limited to, visual “written” marks(e.g., a thin layer of a substance left behind after contact with acrayon, surgical pen, or the like), other written marks outside thevisual spectrum (e.g., a UV-fluorescent paint), guide pins, fasteners(e.g., screws, nails, staples, or the like), radioactive tags, boviecautery burn marks, metallic or nonmetallic devices attached to thedesired landmark site (e.g., a rivet, tack, or the like), or evenmodifications of the patient tissue itself (e.g., notches, inscribedlines, drill holes, or the like). Depiction of one type of landmark 114in the Figures herein merely serves as an example and does not precludethe use of a different type of landmark, even in a similar useenvironment to those depicted, for a particular application of thepresent invention.

Three landmarks 114 a, 114 b, and 114 c are shown in FIG. 3 as havingbeen associated with the primary and secondary patient tissue areas 108and 110. Landmarks 114 a and 114 b are three-dimensional pins which havebeen inserted into the primary and secondary patient tissue areas 108and 110, respectively. Landmark 114 c is a visible two-dimensional crossmark on the secondary patient tissue area 110.

Any landmark 114, regardless of type, will be located at a predeterminedmarking location with respect to the primary and/or secondary patienttissue areas 108 and 110. A three-dimensional landmark, like the markingpins shown as landmarks 114 a and 114 b in FIG. 3 , may also have apredetermined marking trajectory which, like the marking location, holdssome significance for the user. For example, landmarks 114 a and 114 bdo not have parallel trajectories as depicted in FIG. 3 . While themarking trajectory of a three-dimensional landmark 114 (i.e., oneprotruding noticeably from the patient tissue surface) might have nosignificance, the following discussion presumes, for ease of reference,that the marking trajectory of the three-dimensional landmark isintentionally provided and is held substantively constant during thetenure of the landmark at the marking location.

It is contemplated that a landmark 114 will normally be rigidly affixedto a particular marking location on the primary or secondary patienttissue area 108 or 110 in order to serve as a reliable lodestar for theuser. However, in certain situations, the marking location of thelandmark 114 may move (as seen from an outside point of reference) afterplacement, of its own accord, by action of a user, or by action of thesubstrate patient tissue, and these situations do not pass out of thedomain of the present invention merely by virtue of such intentional orunintentional post-placement landmark motion.

The marking location and marking trajectory of each landmark 114 arepredetermined by a user before the landmark is associated with thepatient tissue. This predetermination may occur intraoperatively, as theuser is able to directly see the condition of the surgical site.However, it is contemplated that a predetermination of the desiredmarking location and desired marking trajectory for each landmark 114could be accomplished preoperatively, with reference to preoperativeimaging of the patient tissue. For example, a system similar to that ofco-pending U.S. patent application Ser. No. 13/282,550, filed Oct. 27,2011, titled “System of Preoperative Planning and Provision ofPatient-Specific Surgical Aids” and claiming priority to U.S.Provisional Patent Application No. 61/408,392, filed Oct. 29, 2010 andtitled “System of Preoperative Planning and Provision ofPatient-Specific Surgical Aids”, the entire contents of both of whichare incorporated herein by reference, or any suitable preoperativeplanning system could be used. In this manner, a user can create apatient tissue model for observation, manipulation, rehearsal, or anyother pre-operative tasks.

The term “model” is used herein to indicate a replica or copy of aphysical item, at any relative scale and represented in any medium,physical or virtual. The patient tissue model may be a total or partialmodel of a subject patient tissue, and may be created in any suitablemanner. For example, and as presumed in the below description, thepatient tissue model may be based upon computer tomography (“CT”) dataimported into a computer aided drafting (“CAD”) system. Additionally oralternatively, the patient tissue model may be based upon digital oranalog radiography, magnetic resonance imaging, or any other suitableimaging means. The patient tissue model will generally be displayed forthe user to review and manipulate preoperatively, such as through theuse of a computer or other graphical workstation interface.

Once the user is satisfied with her preoperative planning tasks, virtuallandmarks may be virtually placed on the patient tissue model. In orderto transfer those virtual landmarks to the physical world forintra-operative use, a patient-specific apparatus (shown in FIG. 4 as aguide 416) may be at least partially customized responsive topreoperative imaging of the patient tissue. Accordingly, at least a partof the guide 416 is a patient-specific, single-use, bespoke componentsuited only for use at the indicated surgical site, though one ofordinary skill in the art could create a guide (not shown) which uses apatient-specific “disposable” structure connected to a stock, generic“reusable” carrier.

The patient's name, identification number, surgeon's name, and/or anyother desired identifier may be molded into, printed on, attached to, orotherwise associated with the guide 416 in a legible manner. The guide416 may be made by any suitable method such as, but not limited to,selective laser sintering (“SLS”), fused deposition modeling (“FDM”),stereolithography (“SLA”), laminated object manufacturing (“LOM”),electron beam melting (“EBM”), 3-dimensional printing (“3DP”), contourmilling, computer numeric control (“CNC”), other rapid prototypingmethods, or any other desired manufacturing process.

The guide 416 assists the user by associating a plurality of landmarks114 with patient tissue, each landmark being associated with the patienttissue in at least one of a predetermined marking location and apredetermined marking trajectory. As depicted in FIGS. 4-7 , a base 418may have a lower base surface 520 contoured to mate with both theprimary and secondary patient tissue areas 108 and 110 in a preselectedrelative orientation. The term “mate” is used herein to indicate arelationship in which the contours of two structures are at leastpartially matched or coordinated in at least two dimensions. In thedescribed mating relationship depicted in FIGS. 4-7 as an example of thepresent invention, the lower base surface 520 mates or nests intocontact with the surfaces of both the primary and secondary patienttissue areas 108 and 110 to provide the guide 416 with at least one oflocation and stabilization assistance with respect to the patienttissue.

The lower base surface 520 is spaced apart from an upper base surface422 by a base body 424. A plurality of base apertures 526 extend betweenthe upper and lower base surfaces 422 and 520 through the base body 424.The base apertures 526 are shown here as extending substantiallylongitudinally through the base body 424, but may have any desiredorientation with respect to the base 418.

A plurality of guiding bosses 428 may protrude from the base 418 incertain configurations of the present invention. As shown in theFigures, the guiding bosses 428 protrude substantially longitudinallyoutward from the upper base surface 422, but the guiding bosses may haveany desired orientation with respect to the base 418. Each guiding boss428 has a guiding bore 428 extending therethrough. Each guiding bore 428extends collinearly with a corresponding base aperture 526 to permitinsertion of a landmark 114 through the guide 416. The term “insertionof a landmark through” is intended to encompass both a physical feedingof a three-dimensional landmark itself through the indicated structurefor affixation to the underlying patient tissue (e.g., by penetration),as well as the temporary introduction of a marking device (e.g., a pen,bovie, rasp, other marking actuator or substance dispenser, or the like)through the indicated structure for affixation of a two-dimensionallandmark 114 directly onto the patient tissue.

Each guiding bore 430 and corresponding base aperture 526 cooperativelydefines at least one of the predetermined marking location and thepredetermined marking trajectory (shown in FIG. 5 by trajectory lines532) for an associated landmark 114. In the embodiment shown in FIGS.4-7 , at least one landmark 114 is guided by the guide 416 intoengagement with a marking location in the primary patient tissue area108 (via the rightmost guiding bore 430 in the orientation of FIG. 5 )and at least one landmark is guided by the guide into engagement with amarking location in the secondary patient tissue area 110 (via theleftmost guiding bore 430 in the orientation of FIG. 5 ).

FIG. 6 depicts the guide 416 of FIG. 4 in a slightly differentorientation in space, such that the contour of the lower base surface520 may be seen in more detail. In the orientation of FIG. 6 , theleftmost portion of the lower base surface 520 appears relatively broadand flat and is configured to mate with the surface of the glenoid fossa102 (i.e., the primary patient tissue area 108 here). Thedifferentiation line 312 from FIG. 3 is shown “ghosted” into FIG. 6 andextends somewhat into and out of the plane of the page due to the camberof the depiction in FIG. 6 . With the addition of the differentiationline 312, it can be clearly seen that the rightmost portion of the lowerbase surface 520 does not mate with the primary patient tissue area 108,but instead dips sharply downward relative to the rest of the lower basesurface to mate with the bordering secondary patient tissue area 110.Particularly when there is a “lip” or “rim” between the primary andsecondary patient tissue areas 108 and 110, such as with the glenoidfossa 102, the ability of the lower base surface 520 to concurrentlynest with both of these patient tissue areas may be helpful to the userin quickly and securely nestling the guide 416 down into the desiredmating relationship with the patient tissue.

In FIG. 7 , the upper base surface 422 and protruding guiding bosses 428can be seen in detail. Particularly when a marking trajectory (such asthat shown by trajectory lines 532) is defined by the base aperture 526,with or without the assistance of a guiding bore 430, it may be helpfulfor the guiding bosses 428 to provide a longer guiding structure for theinserted landmark 114. In other words, an elongate landmark 114 mightprecess within a relatively short base aperture 526, but the presence ofthe guiding boss 428 can support and stabilize insertion of the landmarkto better guide the landmark along the predetermined marking trajectory.

FIGS. 8-10 depict the generation of a suitable design for an exampleguide 416 during a preoperative planning procedure. FIGS. 8-10 areexample user views of a computer program for implementing a method usingthe present invention, with a perspective view on the left side of eachFigure and coronal, sagittal (looking distally from underneath theperspective view, as shown), and transverse views, respectively, fromtop to bottom on the right side of each Figure.

In FIG. 8 , a stock glenoid implant 834 is shown associated with aglenoid fossa 102 of a patient's scapula 100, embodied in a modelproduced using preoperative imaging. The glenoid implant 834 may bevirtually placed as desired on the scapula 100 by the user, or may beautomatically placed by the computer program with or without a finalcheck/adjustment by the user. The glenoid implant 834 appears to overlapwith the glenoid fossa 102 in particularly the coronal (top right) andtransverse (bottom right) views of FIG. 8 , but this overlap (whenpresent) is acceptable at the planning stage of FIG. 8 since thephysical glenoid fossa 102 will be prepared via machining or otheralteration(s) as desired during installation of the physical glenoidimplant 834 at the surgical site, and this overlap will be corrected byremoval of the interfering patient tissue. In fact, relatively preciselyplaced landmarks 114 are useful during many surgeries because the sitepreparation procedure commonly erodes, moves, or destroys naturallandmarks which otherwise would help the user with placement ororientation during the surgical procedure.

Implant stem 836, visible in cross-section in the coronal and transverseportions of FIG. 8 , is a tubular anchoring extension from the undersideof the glenoid implant 834 which is inserted into the patient tissue ofthe glenoid fossa 102 during use. One consideration that a user may haveduring placement of the glenoid implant 834 using the computer programshown in FIGS. 8-10 is being able to locate the implant stem 836 in asolid portion of the patient's scapula 100. Another, similarconsideration is the location of screws or other fasteners (not shown)which are commonly used to secure the glenoid implant 834 to the glenoidfossa 102. The user will want to ensure that the proper locations andtrajectories are chosen for affixation of the selected fasteners intorelatively robust areas of the patient's scapula 100. Once the glenoidimplant 834 (including the implant stem 836 and the associatedfasteners) has been virtually placed as desired into a finalinstallation position, the user can decide where to place one or morelandmarks 114, using the guide 416 and relatively early in the surgicalprocess, to facilitate later tasks during the surgery. For example, theuser of the FIG. 8 example may wish to place a guide pin as a landmark114 at each of the marking locations 838 indicated by cross marks. Asshown in FIG. 8 , one marking location 838 a is placed in the primarypatient tissue area 108 and another marking location 838 b is placed inthe secondary patient tissue area 110. For certain surgical procedures,both of these locations may be marked as desired for bone preparationand final implant positioning. Landmarks 114 may be placed before thepatient tissue is altered or modified, with the marking locations 838corresponding to each landmark being specified during the preoperativesurgical planning and/or simulation, or in any other suitable manner.

For example, a guide pin is displayed as a three-dimensional landmark114 at the marking location 838 a spaced apart from the glenoid implant834 over the image of scapula 100 in FIG. 8 , while an aperture orcavity formed in the scapula is shown as a two-dimensional landmark 838b (i.e., represented by a cross mark when seen from above or below)corresponding to a central portion of the glenoid implant in FIG. 8 . Infact, the “negative” aperture-type landmark 838 b of FIG. 8 isconfigured to receive a device shaft implant stem 836 of the glenoidimplant 834, which helps to locate and stabilize the glenoid implantwith respect to the scapula 100. One of ordinary skill in the art wouldreadily be able to instead provide a “positive” pin- or shaft-typelandmark (not shown) protruding from the scapula 100 and adapted to bereceived in a cavity (not shown) of another type of device, in anaxle-type manner.

Optionally, the marking locations 838 may be chosen to comport to commonlandmark 114 placements to facilitate use of standard tools (not shown)with the guide 418. For example, two marking locations 838 may beprovided to indicate a line bisecting the scapula 100 for that patientso that the user has a standardized reference line. In this example,then, generic surgical tools which use the scapula-bisecting line as alandmark in every patient will encounter a patient tissue which has beenstandardized, through use of personalized landmark 114 placements, tomeet a universal expectation of the user. In other words, and moregenerally, the marking location 838 choices can be set for a particularpatient tissue in order to compensate for any peculiarities of thatpatient tissue and accordingly provide the user with a surgical sitethat may be addressed using stock (i.e., not patient-specific) toolsand/or techniques. This type of “universal registration” may beespecially helpful in automation-assisted surgeries.

In FIG. 9 , a user view of the computer program shows a guide blank 940superimposed on the scapula 100. Since the guide 418 will be used toplace the landmark(s) 114 before the surgical site is altered, the lowerbase surface 422 should be designed as a mirror image of the surface ofthe glenoid fossa 102, to mate with the primary and secondary patienttissue areas 108 and 110 as desired. The resolution of the preoperativeimaging scans and the available precision of the chosen manufacturingmethod for the guide 416 will determine how precisely this mating isaccomplished. As is apparent in FIG. 9 , the guide blank 940 contactsand mates with both the primary and secondary tissue areas 108 and 110.The marking locations 838 a and 838 b identified in the view of FIG. 8are represented as a small circle and a cross mark, respectively, on theguide blank 940 in FIG. 9 .

Turning to FIG. 10 , the areas of the guide blank 940 which overlap withthe patient tissue of the scapula 100 have been removed by the computerprogram, generating the complex contour of the lower base surface 520(most apparent in the coronal view). Additionally, base apertures 526and corresponding guiding bosses 428 with guiding bores 430 have beenplaced at the desired marking locations 838, the base apertures andguiding bores being collinear to cooperatively define desired markingtrajectory lines 532. Once the preoperative planning has beenaccomplished, through user input and/or automatic programming, thedesign of the guide 416 is complete and the guide can be manufacturedand prepared for use (e.g., mechanically or chemically cleaned, cured,sterilized, or the like) using any suitable process(es).

FIGS. 11-15 depict various options for configurations of the guide 416.These different configurations, along with other (non-depicted)configurations, of guides 416 can be selected/designed and used by oneof ordinary skill in the art to provide desired landmark-placementproperties for different patient tissues. Structures of FIGS. 11-15 thatare the same as or similar to those described with reference to FIGS.4-10 have the same reference numbers. As with all alternateconfigurations shown and described herein, description of commonelements and operation similar to those in previously describedconfigurations will be omitted, for clarity. In the secondconfiguration, shown in FIGS. 11-12 , the guide 416 is relatively largecompared to that of FIGS. 4-10 (although the Figures herein are notdrawn to scale). As can be seen in the comparative views of FIGS. 10 and12 , the guide 416 of the second configuration (shown in situ in FIG. 12) covers more of the glenoid fossa 102 than does the guide 416 of thefirst configuration (shown in situ in FIG. 10 ). Additionally, theleftmost base aperture 526 and guiding bore 430 (as seen in theorientation of FIG. 12 ) is located substantially in an anterior portionof the secondary patient tissue area 110 for the second configuration,while the corresponding structures in the first configuration arelocated substantially more superiorly within the secondary patienttissue area 110.

The third configuration of the guide 416, shown in FIG. 13 , seemssimilar to that of FIGS. 11-12 , with the addition of at least onemarking notch 1342. The marking notch(es) 1342 may be useful for guidingcontact with the patient tissue for placing a two-dimensional (e.g., viaa pen, bovie, crayon, or other marking device) or three-dimensionallandmark 114 at a desired marking location 838, particularly ifachieving a precise marking trajectory is not important.

FIG. 14 shows a fourth configuration of the guide 416 which includesfeatures from several of the previously defined configurations. Theguide 416 of FIG. 14 has a blockier shape than that of FIG. 13 , whichmay provide efficiencies in design and/or fabrication. That is, theblockier shape of the fourth configuration guide 416 may be bettersuited to a design scheme involving the provision of a generic guideblank 940. In contrast, the contoured upper base surface 422 exhibitedby the third configuration guide 416 requires more extensive smoothingand shaping operations (during the virtual modeling of the computerprogram and/or during physical manufacture), particularly if the basebody 424 is configured to have a substantially uniform thickness by somedegree of mirroring of the lower base surface 520 (dictated by theglenoid fossa 102) with the contour of the upper base surface 422. Inthe fourth configuration of FIG. 14 , the marking notch 1342 of theguide 416 is somewhat rounded and may be operative to assist withplacement of a three-dimensional landmark 114, such as a guide pin, atthe marking location 838, optionally with some degree of imposed markingtrajectory.

A fifth configuration of the guide 416 is shown in FIG. 15 . The guide416 shown in FIG. 15 is similar to that shown in FIG. 16 , with aguiding boss 428 in place of the marking notch 1342, and with theaddition of a handling boss 1544. The handling boss 1544 protrudes fromthe base 418 and is configured for manipulation by the user to at leastpartially control a position of the guide 416. Sometimes the availablemaneuvering space in a surgical field is relatively restricted, and itmay be useful for a forceps, socket driver (perhaps with a frictionalfit or other feature to accept the handling boss 1544), Kocher tool,hemostat, or other user-manipulated handling tool (not shown) toselectively interact with the handling boss to hold the guide 416 steadyand/or to move the guide 416 to a desired position. One or morefeatures, such as indents, apertures, cavities, lugs, undercuts, or anyother suitable structures could be provided to the handling boss 1544 tofacilitate gripping of the guide 416 by any handling tool, in general,and/or by a particular handling tool (perhaps one chosen in conjunctionwith the chosen glenoid implant 834). Optionally, the handling boss 1544may also be a guiding boss 428. However, in some situations it will bedesirable for each of the guiding bosses 428 to be accessible forlandmark 114 placement at the same time that a handling tool is engagedwith the handling boss 1544, so the handling boss could be a separatestructure in those situations.

Regardless of the specific configuration chosen for a particularpatient, the guide 416 will generally be used relatively early in thesurgical procedure. The guide 416 has a base 418 at least partiallycustomized (e.g., custom-manufactured and/or custom-configured)responsive to preoperative imagining of the patient tissue. The base 418of the guide 416 is mated with at least one of the primary and secondarypatient tissue areas 108 and 110 in a preselected relative orientation.When the base 418 is mated with both the primary and secondary patienttissue areas 108 and 110, the mating may be concurrent for both thosepatient tissue areas.

At least one landmark 114 is guided by the guide 416 to a markinglocation 838 in the primary patient tissue area 108 and fixed to theprimary patient tissue area 108 in at least one of a predeterminedmarking location 838 and an predetermined marking trajectory, such as bypassing of the landmark 114 along a marking notch 1342 or through a baseaperture 526 (optionally with the assistance of a guiding bore 430).Optionally, at least one additional landmark 114 may be guided by theguide 416 to a marking location 838 in the secondary patient tissue area110 and fixed to the secondary patient tissue area 110 in at least oneof a predetermined marking location 838 and an predetermined markingtrajectory, such as by passing of the additional landmark along amarking notch 1342 or through a base aperture 526 (optionally with theassistance of a guiding bore 430).

Once the desired number of landmarks 114 are affixed to the primaryand/or secondary patient tissue areas 108 and 110, the guide 416 isremoved from the surgical site in any suitable manner, optionally withthe assistance of a handling boss 1544. When at least one landmark 114is a guide pin or other elongate three-dimensional structure, the guidepin may deflect, if needed, to allow the guide 416 to be liftedlongitudinally off the protruding end guide pin. Alternately, the guide416 may include at least one frangible portion to allow substantiallylaterally-oriented removal of the guide 416 from around the guide pin.As another example, the guide 416 could include one or more slots (notshown) to allow removal of the guide by sliding the guide sideways awayfrom the guide pin.

Regardless of the manner in which the guide 416 is removed from theprimary and secondary patient tissue areas 108 and 110, the landmark(s)114 remain behind and the surgical site attains a configuration akin tothat shown in FIG. 3 . The user can then proceed with the surgicalprocedure with confidence that the landmark(s) 114 are substantiallylocated as configured in the preoperative plan. The patient tissue atthe primary patient tissue area 108 can be altered and the landmark(s)114 that remain as placed using the guide 416 can be used to orient suchalteration or for any other surgical task. For example, a prostheticimplant (such as the glenoid implant 834, when the patient tissue is ascapula 100) may be placed, optionally with the assistance of anotherpatient-specific guide, such as that disclosed in co-pending U.S. patentapplication Ser. No. 13/282,495, filed Oct. 27, 2011, titled “System andMethod for Assisting with Attachment of a Stock Implant to a PatientTissue” and claiming priority to U.S. Provisional Patent Application No.61/408,324, filed Oct. 29, 2010 and titled “System and Method forAssisting with Attachment of a Stock Implant to a Patient Tissue”, theentire contents of both of which are incorporated herein by reference.

FIGS. 16-24 depict a guide 416′ according to certain aspects of a secondembodiment of the present invention. The guide 416′ of FIGS. 16-24 issimilar to the guide 416 of FIGS. 1-15 and therefore, structures ofFIGS. 16-24 that are the same as or similar to those described withreference to FIGS. 1-15 have the same reference numbers with theaddition of a “prime” mark. Description of common elements and operationsimilar to those in the previously described first embodiment will notbe repeated with respect to the second embodiment.

FIG. 16 depicts an example use environment for the guide 416′ of thesecond embodiment. Directional arrow 104′ indicates thesuperior/inferior and anterior/posterior directions. The body ofischium, body of ilium, and body of pubis are shown generally at 1646,1648, and 1650, respectively. The acetabulum 1652 (here, the primarypatient tissue area 108′), which is formed in part by these three bodies1646, 1648, and 1650, has a recessed acetabular fossa 1654 and issurrounded by an acetabular margin 1656 (here, the secondary patienttissue area 110′, shown approximately in FIG. 16 as being outside thedashed differentiation line 312′).

In accordance with the present invention, FIG. 17 depicts a guide 416′including a base 418′, a stem 1758, and at least one spacing arm 1760.The base 418′ has a lower base surface 520′ (shown partially in phantomline in FIG. 17 ) spaced apart from an upper base surface 422′ by a basebody 424′. The lower base surface 520′ is contoured to mate with theacetabulum 1652 in a preselected relative orientation thereto. The base418′ may include a base guide aperture 1762 configured to guideplacement of a landmark 114′ inserted at least partially therethrough inat least one of a predetermined marking location and a predeterminedmarking trajectory, the marking location being in the primary patienttissue area 108′.

The stem 1758 has longitudinally separated first and second stem ends1764 and 1766, respectively. The first stem end 1764 is attacheddirectly to the base 418′, either permanently or removably. The stem1758 extends longitudinally upward from the base 418′ (substantially outof the plane of the paper, in FIG. 17 ).

At least one spacing arm 1760 (two shown) is attached directly to thesecond stem end 1766, either permanently or removably. Each spacing arm1760 is longitudinally spaced from the base 418′ and has an arm guideaperture 1768 laterally spaced from the stem 1758. The arm guideaperture 1768 is configured to guide placement of a landmark (not shownin this Figure) inserted at least partially therethrough at apredetermined landmark trajectory (represented by trajectory line 532′).The spacing arm(s) 1760 are shown in the Figures as extendingorthogonally from the stem 1758 at the second stem end 1766, in order toplace landmarks 114′ in the acetabular margin 1656 (the secondarypatient tissue area 110′) as will be discussed below. The spacing arm(s)1760 could extend at any suitable angle or position from the stem 1758,or could even be smoothly formed as a single integral piece with thestem. In the latter event, the second stem end 1766 may not be clearlydelineated from the spacing arm(s) 1760.

The stem 1758 and spacing arm(s) 1760 could have any of a myriad ofconfigurations, depending upon the application of the present invention.A spacing arm 1760 is used herein to indicate any structure which islocated at some distance from base 418′ contacting a primary patienttissue area 108′, and the spacing arm includes structure which can guidea landmark 114′ to a secondary patient tissue area 110′. A stem 1758 isused herein to indicate any structure which extends between and connectsthe base 418′ and at least one spacing arm 1760.

The guide 416′ may be at least partially customized responsive topreoperative imaging of the patient tissue. For example, the lower basesurface 520′ of the base 418′ could be at least partially configuredthrough the use of computer tomography (“CT”) data of the patient tissueto have a longitudinally downward-protruding portion corresponding tothe acetabular fossa 1656. Additionally or alternatively, the lower basesurface 520′ could be at least partially configured through use ofpatient scans including digital or analog radiography, magneticresonance imaging, or any other suitable imaging means. The patienttissue preoperative images are optionally displayed for review andmanipulation before/during configuration of the lower base surface 520′,such as through the use of a computer or other graphical workstationinterface described above with reference to the first embodiment of thepresent invention. The configuration of the lower base surface 520′ isdescribed herein as being performed using three-dimensional images;however, one or more two-dimensional depictions of the patient tissuemay also or instead be consulted during configuration of the lower basesurface 520′ or any other preoperatively configured structure herein.

The lower base surface 520′ is configured to mate with a primary patienttissue surface 108′, as will be discussed below. In the described matingrelationship, the lower base surface 520′ mates or nests into contactwith the surface of the acetabulum 1652 to provide the base 418′ with atleast one of location and stabilization assistance with respect to thepatient tissue. Though the lower base surface 520′ is shown herein ascovering a substantial portion of the acetabulum 1652, the lower basesurface 520′ may contact any suitable portion of the primary patienttissue area 108′ sufficient to stabilize the guide 416′ in a desiredmanner.

FIGS. 19-21 depict a guide 416′ which is a second configuration of theembodiment of the present invention in the second embodiment of FIG. 17. The guide 416′ of FIGS. 19-21 mainly differs from the guide 416′ ofFIG. 17 in the provision of at least one outrigger 1770 as an extensionof the base 418′. The underside (tissue-contacting) surface of eachoutrigger 1770 forms a portion of the lower base surface 520′ and isaccordingly contoured to mate with a portion of the acetabulum 1652′(the primary patient tissue surface 108′) and the surrounding secondarypatient tissue surface 110′. For example, and as shown in the bottomview of FIG. 20, the outrigger(s) 1770 may extend laterally beyond theremaining acetabular-contacting portion of the base 418′. Theoutrigger(s) 1770 shown in FIGS. 19-21 may contact, or even hook over,the acetabular margin 1656′ to assist with positioning and/orstabilizing of the guide 416′ as shown in the cross-sectional side viewof FIG. 21 . The side view of FIG. 19 and the bottom view of FIG. 20also clearly show a protrusion 1972 formed by the contour of the lowerbase surface 520′ and shaped to mate with the acetabular fossa 1654(shown in FIG. 16 ). Because each patient's bone structure is unique, atleast a portion of the guide 416′ (e.g., the outriggers 1770 and lowerbase surface 520′) is customized responsive to preoperative imaging ofthe patient tissue.

FIG. 21 also shows an orthopedic guidewire 2174 acting as a landmark.One example of a suitable guidewire 2174 is disclosed in co-pending U.S.patent application Ser. No. 13/178,324, filed Jul. 7, 2011, titled“Method and Apparatus for Providing a Relative Location IndicationDuring a Surgical Procedure” and claiming priority to U.S. ProvisionalPatent Application Ser. No. 61/362,722, filed Jul. 9, 2010, and titled“Method and Apparatus for Providing a Relative Location IndicationDuring a Surgical Procedure”, the contents of both of which are herebyincorporated by reference in their entirety. Additionally, FIG. 21 showsa pair of conventionally-configured guide pins acting asthree-dimensional landmarks 114′, though any suitable number,combination, and/or types of two- or three-dimensional landmarks 114′and/or guidewires may be provided for a particular use environment ofthe present invention, and may be associated with either or both of thebase guide aperture(s) 1762′ and the arm guide aperture(s) 1768′.

At least a portion of the guidewire 2174 is insertable through the baseguide aperture 1762′ and into the underlying acetabulum 1652′ when theguide 416′ is mated with the patient tissue in the preselected relativeorientation. Similarly, at least a portion of each of the landmarks 114′is insertable through the arm guide aperture 1768′ and into theunderlying second patient tissue area 110′, shown here as being locatedjust beyond an acetabular margin 1656′, when the guide 416′ is matedwith the patient tissue in the preselected relative orientation.

A distal end 2176 of the landmark 114′ or guidewire 2174 is configuredto remain inserted into the patient tissue when the guide 416′ isremoved from the patient tissue. It is contemplated that the base guideaperture 1762′ and/or arm guide aperture 1768′ will be sized to passover the respective landmark 114′ or guidewire 2174, leaving theseguiding landmark structures in place such as in the configuration shownin FIG. 18 . The landmark(s) 114′ and/or guidewire(s) 2174 may remain inplace for as long as the user desires, though normally will be removedfrom the patient's body before the surgical procedure is concluded. Thelandmark(s) 114′ and/or guidewire(s) 2174 also may be used for anyreason in conjunction with any type or number of processes, during orafter the surgical procedure in which they were installed. A commonguiding function for a landmark 114′ or guidewire 2174 is to guide thepositioning of another structure, either directly (via contact) orindirectly (spaced apart from the guided structure).

FIGS. 22-24 depict a guide 416′ which is a third configuration of thesecond embodiment of the present invention and combines features of boththe previous configurations of the second embodiment, as well as somefeatures of the guide 416 of the first embodiment. The guide 416′ ofFIGS. 22-24 has a very complex base structure with a bifurcated lowerbase surface 520′ which concurrently contacts at least a portion of aprimary patient tissue area 108′ (i.e., contacts an acetabulum 1652 withthe leftmost portion of the lower base surface, as shown in theorientation of FIG. 23 ) and at least a portion of a secondary patienttissue area 110′ (i.e., contacts an acetabular margin 1656 with therightmost portion of the lower base surface, as shown in the orientationof FIG. 23 ). A plurality of guiding bosses 428′ are provided to theguide 416′ of FIGS. 22-24 , including two guiding bosses located on anextended portion 2278 of the base body 424′ to place landmarks 114′ inthe secondary patient tissue area 110′ and one guiding boss located on acentral portion 2280 of the base body to place a landmark 114′ in theprimary patient tissue area 108′.

The guiding boss 428′ located on the central portion 2280 of the basebody 424′ is noticeably longer than the other guiding bosses, and mayserve several functions for the guide 416′. The guiding boss 428′located on the central portion 2280 of the base body 424′ may guide alandmark 1114 through a guiding bore 430′ thereof; may guide a rasp,drill, or other tissue modification tool (not shown) therethrough,optionally providing a “stop” function to limit insertion of the tissuemodification tool into the underlying patient tissue; and/or may serveas a handling boss for user manipulation by hand and/or with a handlingtool.

FIGS. 25-29 depict a guide 416″ according to a third embodiment of thepresent invention. The guide 416″ of FIGS. 25-29 is similar to the guide416 of FIGS. 1-15 and therefore, structures of FIGS. 25-29 that are thesame as or similar to those described with reference to FIGS. 1-15 havethe same reference numbers with the addition of a double “prime” mark.Description of common elements and operation similar to those in thepreviously described first and second embodiments will not be repeatedwith respect to the second embodiment.

The guide 416″ of the third embodiment of the present invention may beused both for associating a plurality of landmarks 114″ with a patienttissue in at least one of a predetermined marking location and apredetermined marking trajectory, and for guiding the removal of apredetermined amount of resection patient tissue and rearrangement of aremaining patient tissue, as will be described. One example of apotential use environment for the guide 416″ of the third embodiment isin conjunction with a surgical procedure to correct a congenital oracquired orthopedic malunion.

FIGS. 25-26 depict a guide 416″ in a first configuration in front andside views, respectively, in a use environment of a patient tissueforming at least a portion of a patient tissue such as, but not limitedto, a femur, humerus, radius, ulna, tibia, fibula, metatarsal, phalange,another type of long bone shaft, a flat bone such as the mandible, afacial bone, a scapula body, a bone of the wrist or ankle, or any otherpatient tissue. In these Figures, the primary patient tissue area 108″is a resection patient tissue 108″ (shaded in FIG. 26 ) and thesecondary patient tissue area 110″ is a remaining patient tissue 110″.The guide 416″ of FIGS. 25-26 is configured to contact the resectionpatient tissue 108″ and the remaining patient tissue 110″ and to guidesurgical contact with the patient tissue.

The guide 416″ of FIGS. 25-26 has a base 418″ having a lower basesurface 520″ contoured to mate with both the resection and remainingpatient tissues 108″ and 110″ in a preselected relative orientation. Thelower base surface 520″ is spaced apart from an upper base surface 422″by a base body 424″, as shown in FIG. 26 .

As shown in FIGS. 25-26 , at least one base aperture 526″ (two shownhere) guides a landmark 114″ into contact with the underlying tissuesurface in at least one of a predetermined marking location 838″ and apredetermined marking trajectory. A plurality of first guide cuttingguide apertures 2582 extend between the upper and lower base surfaces422″ and 520″ through the base body 424″ to permit penetration of atleast one cutting tool (shown schematically at 2584) through the guide416″. The cutting guide apertures 2582 each define at least one cuttingplane location and cutting plane orientation for the cutting tool 2584to make at least one resection cut into the patient tissue.

More specifically, the guide 416″ is configured to cut the resectionpatient tissue 108″ for removal from the remaining patient tissue 110″.The resection patient tissue 108″ is shaded in the Figures, and thecutting plane locations and orientations are chosen to correspond to theborders of the resection patient tissue. Because the resection patienttissue 108″ in the Figures is located intermediate two areas ofremaining patient tissue 110″, at least two cutting plane locations andorientations are needed to excise the resection patient tissue 108″. Ifthere were no remaining patient tissue 110″ to one side (e.g., thetopmost side in the orientation of FIG. 26 ), only one cutting planelocation and orientation would be needed to sever the resection patienttissue 108″. However, the latter situation would not be a true case ofcorrection of a malunion, but merely an amputation. A patient-specificguide 416″ could be produced and used for an amputation if desired.However, though not excluding an amputation situation from applicationof a guide 416″, this description presumes for ease of discussion thatat least two cuts will be made to excise an area of resection patienttissue 108″ from a surrounding area of remaining patient tissue 110″.

Optionally, and as shown in FIG. 26 , at least one guiding boss 428″ mayprotrude from the upper base surface 422″ in association with at leastone of the base apertures 526″ and the cutting guide apertures 2582, asshown in FIG. 26 . The guiding bosses 428″ shown in FIG. 26 may behelpful in avoiding precession of the cutting tools 2584 and therebyassist in guiding the cutting tools to make accurate cuts according tothe preoperative plan embodied in the guide 416″.

Once the resection patient tissue 108″ has been cut and removed from theremaining patient tissue 110″, the remaining patient tissue can berearranged to correct two dimensions of deformity. From the deformedposition of FIG. 26 , therefore, the remaining patient tissue 110″ areascan be collapsed together after removal of the shaded resection patienttissue 108″ for correction in both the proximal-distal andsuperior-inferior dimensions. Accordingly, the patient tissue shown inFIG. 27 is composed entirely of remaining patient tissue and issubstantially cylindrical along a superior-inferior axis 2786.

If there still remains a third degree of deformity, such as rotationabout the superior-inferior axis 2786, to be corrected, then an optionalguide 416″ having a second configuration may be provided as shown inFIGS. 27-28A, the guide 416″ of the second configuration beingconfigured to guide surgical contact with the remaining patient tissue110″ after removal of the resection patient tissue 108″. The guide 416″has a lower base surface 520″ contoured to mate with the remainingpatient tissue 110″ in a preselected relative orientation after removalof the resection patient tissue 108″. A plurality of base apertures 526″permit insertion of at least one landmark (two shown here, at 114 a″ and114 b″) through the guide 416″, the inserted landmarks either beingextant at the surgical site before the guide of the second configurationis introduced or being inserted with the assistance of the guide of thesecond configuration.

At least one of the base apertures 526″ of the guide 416″ of the secondconfiguration defines at least one of the predetermined marking locationand the predetermined marking trajectory for a landmark 114 a″, 114 b″.For example, and as shown in the front view of FIG. 27 and thecorresponding top view of FIG. 28A, the two landmarks 114 a″ and 114 b″have substantially different marking locations and marking trajectoriesfor their penetration into the remaining patient tissue 110″. Thelandmarks 114 a″ and 114 b″ can therefore be used as indicators to aidin correction of the third degree of deformity.

Namely, one portion of the remaining patient tissue 110′ can be rotatedabout the superior-inferior axis 2786 (e.g., as indicated by rotationarrow 2888). Because the resection patient tissue 108″ was fairlyrecently removed, an excision seam 2790 (visible in FIG. 27 ) separatesthe upper and lower (in the orientation of FIG. 27 ) portions 2792 and2794, respectively of the remaining patient tissue 110″ and permitsrelative rotation of those portions to correct the third degree ofdeformity.

Due to preoperative planning of the desired third-dimension rotation andembodiment of that planning in the guide 416″ of FIGS. 27-28A, thelandmarks 114 a″ and 114 b″ can be placed in the respective upper andlower portions 2792 and 2784 of the remaining patient tissue 110″ attrajectories that help guide the rotation during the surgery. Forexample, and as shown in the sequence of FIGS. 28A-28B, the landmarks114 a″ and 114 b″ can be placed relatively askew in the remainingpatient tissue 110″ at predetermined marking trajectories (as shown inFIG. 28A). Relative rotation of the upper and lower portions 2792 and2784 about the superior-inferior axis 2786 then will reposition thelandmarks 114 a″ and 114 b″ into a second orientation with respect toone another—such as the substantially parallel orientation shown in FIG.28B—to indicate to the user that the desired third-dimension rotationhas been achieved. This second orientation can be approximated by theuser's own observation or can be measured or otherwise subjectivelyindicated.

It is contemplated that the landmarks 114 a″ and 114 b″ will each besubstantially rigidly held within its respective upper and lowerportions 2792 and 2784 of the remaining patient tissue 110″, so as notto introduce an unwanted amount of inaccuracy into the rotationprocedure. However, one of the upper and lower portions 2792 and 2794might be configured to move with respect to the guide 416″, with therespective landmark 114 a″ or 114 b″ precessing therein, during therotation procedure.

Optionally, at least one base aperture 526 of the guide 416″ of thesecond configuration may also or instead define a location and/ortrajectory for insertion of a fastener (not shown) into the remainingpatient tissue 110″. Accordingly, the guide 416″ may be configured toguide the placement of at least one fastener to retain the remainingpatient tissue in a desired final arrangement.

The guide 416″ of the second configuration might also or instead includeat least one cutting guide aperture 2582 to permit penetration of acutting tool 2584 through the guide 416″. In this instance, the guide416″ would be configured to define at least one cutting plane locationand orientation for a cutting tool 2584 to make at least one secondarycut into the remaining patient tissue 110″, the secondary cut beingconfigured to assist with the correction of the third dimension ofdeformity.

FIG. 29 depicts a third configuration of a guide 416″ according to thethird embodiment of the present invention. In FIG. 29 , the guide 416″is configured to assist with correction of a malunion or other deformityin the head of a femur, humerus, tibia, phalange, mandible, scapula, orany other suitable bone or other patient tissue. The guide 416″ of thethird configuration 416″ can be used similarly to the guides 416″ of thefirst and second configurations.

FIGS. 30-39 depict a guide 416′ according to certain additional aspectsof the second embodiment of the present invention. The guide 416′ ofFIGS. 30-37 is similar to the guide 416 of FIGS. 1-15 and the guide 416′of FIGS. 16-24 and therefore, structures of FIGS. 30-39 that are thesame as or similar to those described with reference to FIGS. 1-15and/or 16-24 have the same reference numbers with the addition of a“prime” mark. Description of common elements and operation similar tothose in the previously described first embodiment will not be repeatedwith respect to the second embodiment.

FIGS. 30-39 depict fourth through eighth configurations of a guide 416′of the second embodiment of the present invention and combines featuresof the previous three configurations of the second embodiment, as wellas some features of the guide 416 of the first embodiment. The guides416′ of FIGS. 30-39 each have a relatively complex base structure with alower base surface 520′ which is spread across a plurality of extendedportions 2278. The various segments of the lower base surface 520′concurrently contact at least a portion of a primary patient tissue area108′ and at least a portion of a secondary patient tissue area 110′. Aplurality of guiding bosses 428′ are provided to the guides 416′ ofFIGS. 30-39 , including at least one “outboard” guiding boss located onan extended portion 2278 of the base body 424′ to place landmarks 114′in the secondary patient tissue area 110′ and a guiding boss located ona central portion 2280 of the base body to place a landmark 114′ in theprimary patient tissue area 108′.

The guiding boss 428′ located on the central portion 2280 of the basebody 424′ in the guides 416′ of FIGS. 30-39 is noticeably larger thanthe other guiding boss(es), and may serve several functions for theguides 416′. The guiding boss 428′ located on the central portion 2280of the base body 424′ may guide a landmark 1114 through a guiding bore430′ thereof; may guide a rasp, drill, or other tissue modification tool(not shown) therethrough, optionally providing a “stop” function tolimit insertion of the tissue modification tool into the underlyingpatient tissue; and/or may serve as a handling boss for usermanipulation by hand and/or with a handling tool.

The guides 416′ of FIGS. 30-39 differ from each other mainly in thenumber and configuration(s) of extended portions 2278, which may bechosen to aid in stability, positive location, or any othercharacteristic/property of the guide with respect to the patient tissuearea(s) 108′ and/or 110′. As with all embodiments of the presentinvention, any extended portions 2278 present might include at least aportion of the lower base surface 520′ or another patient-specificfeature, or might be generic in structure. In cases where an extendedportion 2278 is generic in structure, the location and/or dimensions ofthe extended portion may have patient-specific aspects in order toprovide some locating function or assistance to the user. The extendedportions 2278 shown in FIGS. 30-39 have locations, configurations,numbers, and are otherwise depicted in arrangements which helpillustrate examples of guides 416′ for various use environments of thepresent invention. The depicted guides 416′ are not limiting as to theextended portions or any other properties of guides (not shown) forparticular use environments of the present invention, which can beprovided by one of ordinary skill of the art in a particular situation.

In FIGS. 30-31 , three extended portions 2278 have segments of the lowerbase surface 520′ which contact different portions of the secondarypatient tissue area 110′ (e.g., an acetabular rim) while a “central”portion of the lower base surface 520′, located on or near the centralportion 2280 of the base body 424′, contacts the primary patient tissuearea 108′.

In FIGS. 32-33 , three extended portions 2278 have segments of the lowerbase surface 520′ which contact different portions of the secondarypatient tissue area 110′ (e.g., an acetabular rim) while a “central”portion of the lower base surface 520′, located on or near the centralportion 2280 of the base body 424′, contacts the primary patient tissuearea 108′.

In FIGS. 34-35 , four extended portions 2278 have segments of the lowerbase surface 520′ which contact different portions of the secondarypatient tissue area 110′ (e.g., an acetabular rim) while a “central”portion of the lower base surface 520′, located on or near the centralportion 2280 of the base body 424′, contacts the primary patient tissuearea 108′.

In FIGS. 36-37 , five extended portions 2278 have segments of the lowerbase surface 520′ which contact different portions of the secondarypatient tissue area 110′ (e.g., an acetabular rim) while a “central”portion of the lower base surface 520′, located on or near the centralportion 2280 of the base body 424′, contacts the primary patient tissuearea 108′.

In FIGS. 38-39 , a single extended portion 2278 has an elongated segmentof the lower base surface 520′ which contacts at least a portion of thesecondary patient tissue area 110′ (e.g., an acetabular rim) while a“central” portion of the lower base surface 520′, located on or near thecentral portion 2280 of the base body 424′, contacts the primary patienttissue area 108′. It is contemplated that a plurality of slightlydifferent guides 416 may be prepared for a particular surgicalprocedure, to allow desired landmark 114 placement regardless ofintraoperative complications. For example, because the user will notnecessarily be able to clear away surrounding patient tissue in situ aspreoperatively planned, several guides 416 based upon differently sized,shaped, and/or oriented guide blanks 940 may be provided. Though each ofthese alternate guides 416 may be configured for placement of landmarks114 in the same positions, the base bodies 424 may mate with differentamounts and/or locations of the primary and/or secondary patient tissueareas 108 and 110. The user can then select one guide 416 from a rangeof alternates available, depending upon how much of the primary and/orsecondary patient tissue area 108 and 110 was actually able to besubstantially prepared for mating with the guide 416. As a variation ofthis option, a range of guides 416 embodying different landmark 114placement schemes could be provided, with the user choosing one of therange of guides 416 once the true condition of the patient tissue can beseen during the surgical procedure. In this latter situation, a range ofsurgical plans are made preoperatively and the user chooses one of thoseplans for proceeding after the surgical procedure is underway.

An prosthetic implant is used as an example herein. However, it iscontemplated that the disclosed guide 416 may be used additionally oralternatively with an instrument, such as that disclosed in co-pendingU.S. patent application Ser. No. 13/282,528, filed Oct. 27, 2011, titled“System and Method for Assisting with Arrangement of a Stock Instrumentwith Respect to a Patient Tissue” and claiming priority to U.S.Provisional Patent Application No. 61/408,376, filed Oct. 29, 2010 andtitled “System and Method for Assisting with Arrangement of a StockInstrument with Respect to a Patient Tissue”, the entire contents ofboth of which are incorporated herein by reference.

While aspects of the present invention have been particularly shown anddescribed with reference to the preferred embodiment above, it will beunderstood by those of ordinary skill in the art that various additionalembodiments may be contemplated without departing from the spirit andscope of the present invention. For example, the specific methodsdescribed above for using the guides 416 are merely illustrative; one ofordinary skill in the art could readily determine any number of tools,sequences of steps, or other means/options for placing theabove-described apparatus, or components thereof, into positionssubstantively similar to those shown and described herein. Any of thedescribed structures and components could be integrally formed as asingle piece or made up of separate sub-components, with either of theseformations involving any suitable stock or bespoke components and/or anysuitable material or combinations of materials; however, the chosenmaterial(s) should be biocompatible for most applications of the presentinvention. The mating relationships formed between the describedstructures need not keep the entirety of each of the “mating” surfacesin direct contact with each other but could include spacers or holdawaysfor partial direct contact, a liner or other intermediate member forindirect contact, or could even be approximated with intervening spaceremaining therebetween and no contact. Though certain componentsdescribed herein are shown as having specific geometric shapes, allstructures of the present invention may have any suitable shapes, sizes,configurations, relative relationships, cross-sectional areas, or anyother physical characteristics as desirable for a particular applicationof the present invention. An adhesive (such as, but not limited to, bonecement) could be used in conjunction with the system and methoddescribed herein. The guide 416 may include a plurality of structurescooperatively forming the base body and temporarily or permanentlyattached together in such a manner as to permit relative motion (e.g.,pivoting, sliding, or any other motion) therebetween. Any structures orfeatures described with reference to one embodiment or configuration ofthe present invention could be provided, singly or in combination withother structures or features, to any other embodiment or configuration,as it would be impractical to describe each of the embodiments andconfigurations discussed herein as having all of the options discussedwith respect to all of the other embodiments and configurations. Adevice or method incorporating any of these features should beunderstood to fall under the scope of the present invention asdetermined based upon the claims below and any equivalents thereof.

Other aspects, objects, and advantages of the present invention can beobtained from a study of the drawings, the disclosure, and the appendedclaims.

1. A computer-assisted surgery method for assisting a positioning of aglenoid implant on a scapula, the computer-assisted surgery methodcomprising: obtaining a virtual model of a glenoid surface of a scapula;identifying a penetration landmark in the glenoid surface of thescapula; obtaining a planned positioning of a glenoid implant relativeto the penetration landmark; determining a surgical plan based on theplanned positioning of the glenoid implant; and generating andoutputting at least one patient-specific guide model representative ofthe surgical plan.
 2. The computer-assisted surgery method according toclaim 1, further comprising calculating and outputting a volume of boneremoval as a function of the planned positioning.
 3. Thecomputer-assisted surgery method according to claim 2, whereincalculating and outputting the volume of bone removal as a function ofthe planned positioning includes updating the volume of bone removal asthe planned positioning varies.
 4. The computer-assisted surgery methodaccording to claim 1, wherein determining the surgical plan includesidentifying two non-parallel reaming axes.
 5. The computer-assistedsurgery method according to claim 4, wherein generating and outputtingthe at least one patient-specific guide model representative of thesurgical plan includes generating one said patient-specific guide modelwith guides for the two non-parallel reaming axes.
 6. Thecomputer-assisted surgery method according to claim 1, furthercomprising driving an apparatus for fabricating at least onepatient-specific guide from the at least one patient-specific guidemodel.
 7. The computer-assisted surgery method according to claim 1,wherein identifying a penetration landmark in the glenoid surface of thescapula includes identifying a deepest point in the glenoid surface. 8.The computer-assisted surgery method according to claim 1, whereinobtaining a planned positioning of a glenoid implant relative to thepenetration landmark includes obtaining a model of the glenoid implant.9. The computer-assisted surgery method according to claim 8, whereinobtaining the model of the glenoid implant includes obtaining the modelof a stock version of the glenoid implant.
 10. The computer-assistedsurgery method according to claim 8, wherein obtaining the model of theglenoid implant includes obtaining the model of the glenoid implanthaving a stem.
 11. The computer-assisted surgery method according toclaim 8, wherein obtaining the model of the glenoid implant includesobtaining a positioning of fasteners for securing the glenoid implant tothe scapula.